Add per-user library settings, folder passwords, and a still picker.

Settings manages folders, thumbnail defaults, and passwords for the signed-in account, and choosing an image now browses saved stills instead of only the desktop file dialog.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/api/library/folders/[id].patch.ts

@@ -1,6 +1,22 @@
 export default defineEventHandler(async (event) => {
-  assertLibraryAccess(event)
-  const id = getRouterParam(event, 'id')
-  const body = await readBody<{ name?: string }>(event)
-  return await renameFolder(String(id), String(body?.name || ''))
+  const { owner } = assertLibraryOwner(event)
+  const id = String(getRouterParam(event, 'id') || '')
+  const body = await readBody<{
+    name?: string
+    thumbnailDefault?: boolean
+    password?: string | null
+    currentPassword?: string
+  }>(event)
+  const folder = await updateFolder(owner, id, {
+    name: body?.name,
+    thumbnailDefault: body?.thumbnailDefault,
+    password: body?.password,
+    currentPassword: body?.currentPassword
+  })
+  if (body?.password) {
+    setFolderUnlock(event, folder.id, passwordVersion(folder.passwordHash))
+  } else if (body?.password === '') {
+    clearFolderUnlock(event, folder.id)
+  }
+  return publicLibrary(event)
 })